Typical foldable wheelchairs support the seat occupant with a sling-like seat and back extending between the two sides of the wheelchair. The side frames of the wheelchair are joined by a cross-frame assembly that performs a scissor-like folding movement. With this, the wheelchair can be adjusted between a use configuration and a folded configuration for storage and transport.
Unfortunately, the sling seats and backs typical of the prior art are ergonomically incorrect and produce discomfort and poor posture, particularly when used for extended periods of time. Indeed, studies have shown that prolonged use of sling-style chairs have produced negative effects on the seat occupant's posture, comfort, and overall health. In certain cases, extended use of sling-style seats and backs has resulted in pressure sores, a curving of the spine into a kyphotic geometry, and a posterior tilting of the pelvis thereby causing further discomfort and maladies.
It is generally agreed that a person's back and posterior are best supported by a resilient cushion having sufficient rigidity to prevent the bowing and resultant discomfort inherently produced by sling seats and backs. Accordingly, the prior art has sought to remedy the deficiencies of sling arrangements by the use of removable seat and back cushions that use the sling arrangement as a support base. The removable cushions are normally sold as after-market accessories.
While such arrangements can provide a seat occupant with much needed support, the removable cushions suffer from a number of drawbacks. For example, the user must remove the cushion prior to folding the wheelchair, find a place to place the cushion during transport or storage, and then reinstall the cushion when the chair is again ready to be used. Furthermore, such cushions often fail to stay in a fixed position whereby they, and possibly the seat occupant, slide into a disadvantageous and uncomfortable position. Still further, the removable cushions can be lost, damaged or soiled, or reinstalled incorrectly.
In light of the foregoing, it becomes clear that there remains a need in the art for ergonomic foldable seat and back cushions for use in relation to folding chair constructions that provide comfortable, ergonomically sound support while enabling the chair to be folded for storage and transport without a need for being removed from the chair frame.